Slack cable switch



March 8, 1932. F, B, PEEBLES 1,848,972

SLACK CABLE SWITCH Filed March 19, 1951 2 Sheets-Shet l /f BY 9% ATTORNEYS March 8, 1932. F, B, PEEBLES 1,848,972

SLACK CABLE SWITCH Filed March 19, 1951 2 Sheets-Sheet 2 INVENTOR E ATTORNEYS the swinging frame;

Patented Mar. 8, 1932 UNITED STATES PATENn OFFICE B. PEEBLES, OF HUDSON, NEW YORK, ASSIGNOR T0 GIFFORD-WOOD COMPANY,

-OF HUDSON, NEW YORK, A CORPORATION OF NEW YORK sLAcx CABLE SWITCH j Application med umn 19,1931. serial No. 523,923. i

able construction which'may be adapted for usev with installations of many di'erent types, both those already in use and new installations, particularly trolley bucket installations.

In the accompanying drawings showing Fig. lis a side elevation of a hoist drum showing the improved mechanism mounted adjacent thereto;

' Fig. 2 is an elevation viewedv from the right end of Fig. 1; v Fig. 3 is an enlarged vertical section showing particularly the adjustable foot piece on Fig. 4 is a simplified wiringdiagramshowing the manner in which the switch controls the motor circuit;

Fig. 5 is an elevation with parts in section j showing another form ofthe invention;

Fig. 6 is a 4fragmentary plan view of the form of Fig. 5the drum being shown in dot and dash lines;

Fig. 7 is a detailed elevation of the adjustable foot piece used in the form of Fig. 5;

Fig. 8 is a. plan view of the same; and

Fig. 9 i's a perspective viewfofthe eccentric disk used as a stop in connection with the swinging frame of Fig. 5.

Referring particularly to Figs. 1, 2 and 3, there is shown the baseV 15 of ka hoist unit which may be employed with a trolley bucket system, mine hoist or the like. Mounted in bearings on the base 15 is a drum 16 which is driven through gearing (indicated in dot and dash lines) by a motor M(Fig.4). A hoist cable 17 has one end secured to the drum 16 andis wrapped around the same, as shown in Fig. v2, the hoist cable being guided by guide sheaves (not shown) to the bucket which is raised and lowered as the drum is driven in reverse directions.

Mounted on the base 15 is a switch 18 which, as shown in Fig. 4, is in the motor circuit and vpushed inwardly.

is so arranged that it stops the motor when opened. p Preferably, but not necessarily, the switch 18 is of the type having a plunger or contact Amember ,19 projecting outside the switch-member, as shown, the switch being normally opened by a spring 19a but-being closed whenever said contact member is vPivotally mounted ony the base 15 adjacent the drum A16 is a frame which moves responsive tovariations in tension of the hoist cable 17. This frame, as shown, consists of two side members 20 'connected together by a rod or shaft 21 on which a sheave 22 is slidably mounted, said sheave being in Vcontactfwith the hoist cable 17 The members20 are pivoted-about a rod 23' secured upon the base 15; and to cause the frame to hold the sheave 22 against the Vhoist cable-17, there isV an eirtension frame-24 carrying a counterweight 25. The counterweight 25 is of such mass as to maintain constant pressure of the sheave against the hoist cable `so that the hoist cable is constantly in the groove of 1 the sheave. Thus the sheave'r22 will travel longitudinally of the rod or shaft 21 as the cable 17 unwraps from the drum 16.

It lwill be clear that when the vcable 17 slackens, the `frame will rockin a clockwise direction, as viewed in Fig. 1, the weights 25 maintaining contact Vbetween the sheave and the cable whatever the position of the latter. It will also be obvious that a considerable slack will be created in the cable each time the bucket Vreaches thel lower limit ofits travel. At this time, the hoist motor should be stopped. Stoppage of the hoist motor is effected through the switch 18, whose contact member 19 is released by an adjustable foot piece 26 carried by the frame; the parts being so constructed-and arranged that each time the cable slackens the foot piece is lifted, relative to the contact memberI 19,' whereupon the switch automatically opens. As soon as the switch opens, the motor stops because of the solenoid brake S, thus stopping the hoist drum-and thebucket. j

It will be observed that the adjustable foot piece 26 is longitudinally adjustable because ofthe series of holes 27 in said foot piece,

said holes extending longitudinally thereof and permitting the foot piece to be adjusted substantially vertically relative to contact member 19, adjustment being effected by the bolts 28.

lVhen the bucket is suddenly stopped, the hoist cable 17 will whip back and forth and may oven jump out of the groove and sheavc 22 unless means are provided to control the movement of the cable. To prevent the cable from umping out of the groove of the sheave, a rod 29 is secured to the side members 2() of the frame and passes transversely across the frame adjacent the edge of the sheave, as clearly shown. Thus the frame will move with the cable and the cable cannot jump out of the groove, which would make it impossible to opera-te the hoist unit as the switch 18 would remain open.

Referring now to the form of the invention shown in Figs. 5 and 6, there is a base 30, a hoist drum 31, a hoist cable 32 and a pivoted frame, including side members 33 and a connecting member 33a. Extending between the free ends of the members 33 is a rod or shaft 34 on which is slidably mounted the sh'eave 35 having contact with the hoist cable 32, as shown. The frame is pivoted as upon a rod 36 so as to swing responsive to fluctuation-s in the tension of the hoist cable.

The slack cable switch is indicated diagrammatically at 37 and has a projecting contact member 38 with which an adjustable foot piece 39 is normally in contact. The adjustable foot piece, as shown in Figs, 7 and 8, has a flange 40 for making contact with the contact member and a bore 41 by which it is mounted on the rod 36 to oscillate with the frame member 33. The foot piece 39 also has an arcuate slot 42 and a bore 43 passing through said slot and through the end of the member 33 on which the foot piece is mounted. rl`hus, an angular adjustment of the foot piece 39 relative to the member 33 is permitted, so as to adapt the position of the foot piece to the relative positions of the frame member 33 and the contact member 33 with which the flange 40 contacts.

To control the swinging movement of the frame, stop members are provided on the plate 44 supported by the base 30. The plate 44 has a series of perfor-ations 45 arranged in an arc whose center is the axis of the pivot rod 36; and two stops 46, 47 are provided, each being secured by a bolt in one of the perforations 45 in such a position as to be struck by the edge of one of the frame members 33 as it oscillates responsive to fluctuations in the tension of the hoist cable( As the frame member 33 is normally in contact with the upper stop member 47 and as there is a certain normal position for said frame, it is preferred that this stop member be made adjustable so as to have an edge contact with the frame member 33 when the sheave 35 is resting lightly on the cable 32. As the angle of the cable 32 varies with different installations, and as it is desirable to hold the sheave 35 in constant engagement with the hoist cable, a nice adjustment of the stop member 47 is almost indispensable and this is permitted in the preferred construction by making the stop member 47 an eccentric, best shown in F ig. 9, providing a bore 48 through which a bolt 49 (Fig. may pass, 'the bolt 49 permitting the workman, during erection of the hoist unit, to oscillate the eccentric 47 about the bolt as a pivot to bring the edge of the eccentric in proper engagement with the edge of frame member 33. lVhen the proper engagement has been effected, the workman will then drill the cccentric 47, as indicated at 50 (F ig. 9) at the same time drilling the plate 44; and the adjustment will be made permanent by means of a small bolt 51 passing through the two holes so drilled. The eccentric 47 serves as a stop to prevent such movement of the frame as would break the switch and may be accurately adjusted to insure, in conjunction with the foot piece 39, proper operation of the switch, that is full movement of the contact member 3S. It will be obvious that by means of the slot 42 and the holes 45 a very nice adjustment may be made to insure proper operation oit' the switch, irrespective of the angle of the rope, and hence the device may be adapted to all conditions met with in the field. Furthermore, the mechanism is adapted to operate the switch when the rope becomes very slightly slack, or quite slack, as may be desired for a particular installation, and thus the invention provides an extremely sensitive slack cable switch.

To prevent the cable from jumping out of the groove of the sheave because of the whipping action referred to above, a rod 52 extends between the members 33 adjacent the periphery of the sheave 35, as shown in Figs. and 6.

Obviously, the present invention is not restricted to the particular embodiments thereof herein shown and described.

llVhat I claim is 1. Slack cable switch apparatus comprising, in combination, a hoist cable; a support; frame having a sheave at one end engaged with the cable, said frame being pivotally mounted on the support and extendingr on both sides of its pivot; a counterweight on the opposite side of the pivot from the sheave and serving to press the sheave against the cable; a selfopening switch mounted adjacent the frame and having a spring and a Contact member which is outwardly projected by the sijn-ing; and an adjustable foot piece on the frame engaging the contact member to hold the switch closed; the parts being so constructed and arranged that a slackening in tension of the cable causes a swinging of the frame to lift the foot piece off the contact member, thereby to effect opening of the circuit controlled by the switch. f

2. Slack cable switch apparatus comprising, in combination, a hoist cable; a support; a frame having a sheave at one end engaged with the cable, said frame being pivotally mounted on the support so as to press the sheave against the cable at all times; a selfopening switch mounted adjacent the frame and having a spring and a contact member which is outwardly projected by the spring; and an adjustable foot piece'on the frame engaging the contact member to hold the switch closed; the parts being so constructed and arranged that a slackening in the tension of the cable causes a swinging of theframe to lift the foot piece ofi' the contacty member, thereby to effect opening of the circuit controlled by the switch.

3. Slack cable switch apparatus comprising, in combination, a hoist cable; a support; a frame pivoted on the support and having a sheave at one end engaged with the cable, said frame having.l a shaft along which the sheave may slide and being pivotally mounted so as to press the sheave against the cable at all times; a hoist drum about which said hoist cable is wrapped; the frame being adjacent the hoist drum so that the sheave travels back and forth along the shaft as the cable is wrapped upon and unwrapped from the drum; means on the frame to hold the cable against jumping out of the groove of the sheave; a self-opening switch mounted adjacent the frame; and means on the frame to hold the switch closed; the parts being so constructed and arranged that a slackening inthe tension of the cable causes a swinging of the frame, to e'ect opening of the circuit controlled by the switch.

4. Slack cable switch apparatus comprising, in combination, a hoist cable; a support; a frame having a sheave at one end engaged with the cable, said frame being pivotally mounted on the support so as to press the sheave against the cable at all times; a selfopening switch mounted adjacentthe frame and having a spring and a contact member which is outwardly projected by the spring; stops adjustably mounted adjacent the frame in the path in which' it swings to limit the arcuate movement thereof; and means on the frame engaging the contact member to hold the switch closed; the arts being so constructed and arranged t at a slackening in the tension of the cable causes a swinging of the frame to releasek the Contact member, thereby to effect opening of the circuit controlled by the switch.

5. Slack cable switch apparatus comprising, in combination, a hoist cable; a support; a frame having a sheave at one end engaged withk the cable, said frame being pivotally mounted on the support so as to press the ',sheaveagainst the cable: at all times; aself- :opening switch mounted adjacent the frame; 4stops adjustablymounted adjacent theframe in the v pathin which it swings to limit thearcuate movement thereof, one of said stops lbeing van eccentric disk, one edge of which engages a part of the frame, said disk ,being initially angularly adjustable to vary the extent to which said frame is movable in one direction and being rigidly secured in the adjusted position; and means on the frame engaging the switch to hold the switch closed; the parts being so constructed and arranged that a slackening in the tension of the cable causes swinging of the frame to release the switch, thereby to effect opening of the circuit controlled by the switch.

6. Slackv cable switch apparatus comprising, in combination, a hoistcable; a support; a frame having a sheave at one end engaged with the cable, said frame being pivotally mounted on the support so as to press the sheave against the cable at all times; a selfopening switch mounted adjacent the frame and having a spring and a contact member which is outwardly projected by the spring; stops adjustably mounted adjacent the frame in the path in which it swings to limit the arcuate movement thereof; and an adjustable foot piece on the frame engaging the contact member to hold the switch closed, the parts being so constructed and arranged that a slackening in the tension of the cable causes a swinging of the frame to lift the foot piece ofl the contact member, thereby to effect opening of the circuit controlled by the switch.

7 Slack cable switch apparatus comprising, in combination, a hoist cable; a support;I a framehaving a sheave at one end engaged 'with the cable, said frame being pivotally mounted on the support so as to press vthe sheave against the cable at all times; a selfopening switch mounted adjacent the frame and having a spring and a contact member which is outwardly projected by the spring; and an adjustable foot piece on the frame engaging the contact member to hold the switch closed; said foot piece being longitudinally adjustable on that part of the frame to which it is attached and extending directly over said contact member; the parts being so constructed and arranged that' a slackening in the tension of the cable causes a swinging of the frame to lift the foot piece olf the contact member, thereby to effect opening of the circuit controlled by the switch.

8. Mechanism for actuating slack cable switches comprising, in combination, a support a frame swingably mounted on the support and having a sheave in contact with the cable whose slackening is to actuate the switch; a foot piece ivoted on the pivot axis of the frame and aving an arcuate slot whose center of curvature is said pivot axis and also having an extension for Contact with the Contact member of the switch; and means to secure said foot piece to the frame.

In testimony that I claim the foregoing as my own, I have hereto aixed my signature.

FRANK B. PEEBLES. 

